The present invention relates to a swivel joint, especially for seats with an adjustable backrest in which two link members are tiltably connected to each other by a pivot pin and which is provided with a device for angularly adjusting the link members with respect to each other and for fixing the same in any adjusted position and comprising an internal gear integral with one of the members and meshing with the spur gear integral with the other of the members and in which the turnable pivot pin is provided with an eccentric portion on which one of the gears is mounted.
A swivel joint of the above-mentioned construction is disclosed in the German Pat. No. 12 97 496 in which FIG. 4 shows a swivel joint in which the link member connected with the seat is integral with a spur gear turnably mounted on an eccentric portion of the pivot pin. The link member connected to the backrest is integrally connected with an internal gear meshing with the spur gear and mounted by means of a disc on a central portion of the pivot pin. The afore-mentioned disc carrying the internal gear on the central portion of the pivot pin is formed from elastic material. This elastic annular disc serves to compensate any machining tolerances. Even though tolerances of the gearing as well as that of the pivot pin and the mounting thereof may be compensated by the elastic annular disc, this elastic annular disc is not able to serve for damping the noise produced during adjustment of the swivel joint especially in the region of the teeth of the gears since the noise during the metallic engagement of the gears will evidently not be dampened by this known arrangement.
Additional known arrangements for tolerance compensation, as for instance the arrangement of the eccentric on the pivot pin with intermediate spring buffers are not adapted to reduce the noise occurring during the adjustment of the swivel joint.